Hand-held electrically driven domestic appliances, such as hand blenders, are used nowadays in many homes and kitchens. This type of hand blender, such as the hand blender described in EP 2 571 037 A1, generally has a speed switch for smoothly controlling the speed of the motor which drives the hand blender. By means of the speed switch or controller, in the following generally referred to as the operation element, the speed or the rotation speed of the motor can be adjusted from complete standstill to a maximum rotation speed of the motor. The adjustment is made according to the movement path or the operation path, such as the depth of pushing in the speed switch, or the force applied to the speed switch, mostly smoothly or continuously. A portion of the prior art hand blender is shown in FIG. 8, reference number 801 depicting the speed switch of the hand blender 800.
This type of hand-held electrically driven domestic appliance, such as the prior art hand blender, has a problem, namely that the operation path (e.g. the depth of pushing in) of the speed switch is relatively small, but nevertheless a large rotation speed range of the motor from zero to maximum speed must be able to be actuated/controlled. This makes it difficult for the user of the appliance to select and hold a specific control, such as a specific speed, which is preferred by the user or which is ideal for a specific application or process.
Another problem associated with conventional hand-held electrically driven domestic appliances, such as hand blenders, is that the speed may change with a constant position of the operation element (e.g. a constant depth of pressing in) due to a change in the load as a result of the product to be processed (such as the food that is to be broken up), and this may lead to an undesirable processing result. This type of load change may be brought about e.g. when processing pasty, sticky foods that form balls such as dough, honey, thick soups as well as with food processor applications where food is fed in non-uniformly (e.g. cutting slices, grating, juice extraction, mincing), with which a required start-up torque is very high and the required torque then decreases greatly.